\version "2.17.26"

#(set-global-staff-size 24)

harmonies = \new ChordNames \chordmode {

  s1.*4

  c2.:m7.5-    c:7
  c:7          c4.:/g c

% first ending
  c2.:m7.5-    c:m7
  c:m7         c:7.9-

% second ending
  c:m7.5-      c:7.5+

} % harmonies 


melody = \new Staff {

  \new Voice {

    \key c \major
    \time 12/8

    R1.*4 \break

    \repeat volta 2 {
      R1.*2
    } \alternative {
      {
        \tag #'tweaked {
	  \once \override Score.VoltaBracket #'vertical-skylines = #'()
	  \once \override Score.VoltaBracket #'Y-extent = #'(-0.5 . 2.0)
	} % tag
	R1.*2 \break
      } % first
      {
	R1.*2
      } % second
    } % repeat

    R1.*2
    \bar "|."

  } % Voice

} % melody


\score {
  <<
    \harmonies
    \removeWithTag #'tweaked \melody
  >>
} % score


\score {
  <<
    \harmonies
    \melody
  >>
} % score